1. CIS 488/588 Bruce R. Maxim UM-Dearborn
Unreal Karma Actors
CIS 488/588
Bruce R. Maxim
UM-Dearborn
12/9/2018

2. Karma Unreal Physics Engine
Used to make objects in your scene react to physical forces (gravity, explosions, collisions)
Many aspects of the Karma engine can only be exploited using Unreal Script
To build rag doll characters requires the use of Maya or other external 3D packages and the Karma Authoring tool known as KAT
There are some things that can be done with Karma objects inside UnrealEd
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3. Karma Theory - 1
The Karma engine make use of a special type actor known as a KActor
KActors have the Physics property (found under the Movement category) set to PHYS_Karma
This setting passes control of an object’s movement to the Karma physics engine
How the object reacts is determined by the setting KParams property under the Karam category in the object’s Properties window
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4. Karma Theory - 2
If you keep drilling down you will find lots of properties that are editable (mass, buoyancy, friction)
The bBlockKarma property (under the Collision category) determines whether a KActor will react to placeable item found in the current map
Setting bBlockKarma to True makes collisions with Karma objects and Actor surfaces possible and reactable
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5. Creating Simple Karma Actor Tutorial 11.1
Use the map file Tutorial11_01_Start.ut2
Open the StaticMesh browser and locate the package AWHardware, find the Decorations category, and select sh_barrel_M_JM
Use the RMB and add the barrel to the level using the “add Karma Actor” item from the context menu
You will need to adjust the position of the barrel
Rebuild the level, save, and test the level
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6. Creating Simple Karma Actor Tutorial 11.2
To see anything happen with the barrel you will need to shoot it with something big, like the RocketLauncher (this is even true if the barrel started the level hovering in the air)
To make the barrel come alive when you first enter the level, open the Properties window, and drill down Karam>Kprams>KarmaParams myLevel>KaramPrarams
Set the property KStartEnabled to True
Rebuild, save, and test the level
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7. KBS Joints - 1 Tutorial 11.2 Use the map file Tutorial11_02_Start.ut2
Use the StaticMesh browser to open the package Chapter11.utx, in the LightSystem group select ShortChain
Use the RMB button to open the context menu, select Add Karma Actor, and add the chain to the middle of the ceiling
Use Crtl-W to duplicate the chain and put a copy of the chain beneath the first chiain
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8. KBS Joints - 2 Tutorial 11.2
Open the Static Mesh browser and select Light inside the Chapte11 package LightSystem group
Use the RMB and add the Light as a Karma Actor from the context menu to the end of the chain
If we run the level now, shooting the light just causes it to fall to the floor
Open the Actor class browser, expand Kactor>Kconstraint and select KBSJoint
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9. KBS Joints - 3 Tutorial 11.2
Use the RMB to add a KBSJoint near the lamp
Position the KBSJoint so that it connects the chain to the ceiling
Use Ctrl-W duplicate the KBSJoint and place it between the chain pieces
Use Ctrl-W duplicate the KBSJoint and place it between the chain and the light
Open the Properties window for the KBSJoint on the ceiling and expand the KarmaConstraint category
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10. KBS Joints - 4 Tutorial 11.2
Set the value of KConstraintActor1 to the name of the top chain piece
Open the Properties window for the KBSJoint between the two chain pieces
Set the value of KConstraintActor1 to the name of the top chain piece and set the value of KConstraintActor2 to the name of the bottom chain piece
Open the Properties window for the KBSJoint between the chain and the light
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11. KBS Joints - 5 Tutorial 11.2
Set the value of KConstraintActor1 to the name of the bottom chain piece and set the value of KConstraintActor2 to the name of the light
It is possible that you may need to go into the Properties window for each of the Karma actors and set the value of bHighDetailOnly to False in the KaraParams dialog (otherwise they may not react to speed up game play)
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12. KConeLimit Tutorial 11.3 Use the map file Tutorial11_03_Start.ut2
Open the Actor class browser, expand KActor>Kconstraint, and select KConeLimit
Use the RB and choose Add KConeLimit from the context menu to add the actor near the Light
Rotate the KConeLimit so the red arrow points down the z-axis
You can adjust values of KConstraintActor1 and 2 to point the two chain pieces and adjust the value of KHalfAngle to get the right effect
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13. Dynamic Bridge - 1 Tutorial 11.4
Use the map file Tutorial11_04_Start.ut2
If we run the level and shoot the bridge it will simply collapse
We can add KHinge actors to make it bouncy instead
Open the Actor class browser, exapnd Kactor>Kconstraint, and select Khinge
Use the RMB to add the Khinge to connect the first bridge piece and the wall
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14. Dynamic Bridge - 2 Tutorial 11.4
Rotate the KHinge so that the arrow points towards the wall
Use Ctrl-W to duplicate the KHinge and place the copy to connect the first and second bridge pieces
Continue the process until you reach the far end of the bridge
Open the Properties window for the first Khinge and expand the KarmaConstraint category
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15. Dynamic Bridge - 3 Tutorial 11.4
Select the KarmaConstraintActor1 property, click the Find button and then click the first bridge piece
For the KHinges connecting to bridge pieces you will need to do this for bridge pieces on both sides of KHinge to set KarmaConstraintActor1 and KarmaConstraintActor2
You may need to set bHighDetailOnly to False
Rebuild, save, and test
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16. Working Fan - 1 Tutorial 11.5 Use the map file Tutorial11_05_Start.ut2
To get the fan do more that fall off the wall when shot, you need to use a KHinge
Open the Actor class browser, expand KActor>Kconstraint, and select KHinge
Use the RMB to add the Khinge near the fan, move the KHinge to the center of the fan, and rotate it to ensure its axis matches the fan
Open the Properties window for the KHinge
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17. Working Fan - 2 Tutorial 11.5
Set the value of KConstraintActor1 property to point to the fan
Change the KHingeType property to HT_Motor to give the fan constant motion
Change the value of KDesiredAngVel to and the value of KMaxTorque to 100
Rebuild the map, save, and test (when you shoot the fan with the RocketLauncher it will run continuously)
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18. Creating Catapult – 1 Tutorial 11.6
Use the map file Tutorial11_06_Start.ut2
Open the Actor class browser, expand Kactor>Kconstraint, and select KHinge
Use the RMB and place a KHinge near the fromt of the catapult facing the bridge
Rotate the KHinge so that it points down the y-axis
Set the KConstraintAcor1 property to point to the catapult
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19. Creating Catapult – 2 Tutorial 11.6
Change the KHingeType to HT_Springy
Change KStiffness to 5000
Change Kdampening to 250 (so the catapult will not swing back and forth too much)
To add a trigger, open the Actor class browser, exapnd Triggers, select UseTrigger
Use the RMB to add a UseTrigger near the catapult
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20. Creating Catapult – 3 Tutorial 11.6
Open the Properties window for UseTrigger, expand he Advanced category, and set bHidden to False
Expand the Events category and set the Event property to TriggerCatapult
Open the Properties window for the KHinge, expand the Object category, change value of InitialState to ToggleDesired
Expand the KarmaConstraint category and set KAltDesiredAngle to (90 degrees)
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21. Creating Catapult – 4 Tutorial 11.6
To associate the UseTrigger with the KHinge, expand the Events category, and set the Tag property to TriggerCatapult
To test the catapult place a copy of the Karma barrel on top of the catapult (remember to use add Karma Actor)
Open the barrel Properties window, set bHighDetailed to False, bKStartEnabled to True, and set Kmass to 0.5
Rebuild the level, save, and test it
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22. Using Ragdolls - 1 Tutorial11.7
Use the map file Tutotial11_07_Start.ut2
You need an actor to serve as a template for your ragdoll, any KActor will do (so start with the barrel) – remember to use “add KActor”
Open the Properties window for the new KActor, expand the Display category, change the DrawType property to DT_Mesh
To set the Mesh property, open Animation browser, open the HumanMaleA package and select the MercMaleA mesh, and click Use button
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23. Using Ragdolls - 2 Tutorial11.7
Move the new model so that the ragdoll right hand is placed inside the KBSJpoint at the bottom of the chain
Open the Properties window of the KBSJoint, expand the KarmaConstraint category, and set the KConstraintActor2 to point to the MercMaleA mesh
The correct mesh is displayed, but behavior is not right
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24. Using Ragdolls - 3 Tutorial11.7
Open the Property window for the ragdoll, expand the Movement category, and change the Physics property value to PHYS_KarmaRagDoll
Expand the Karma category, drill down to the KParams property, click the Clear button
Select the KarmaParamsSkel and click the New button
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25. Using Ragdolls - 4 Tutorial11.7
Expand the KParams category and drill down so that you can set the Kskeleton property to Male
You may also need to set bHighDetailOnly to False
Rebuild, save, test, and fiddle with parameters to get the right effects
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26. KAT
There is a Karma authoring tool that let’s you build your own KActors
This requires the use of a 3D model exported from Maya or similar tool
Using KAT you can create your own rag dolls and other reactive devices
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